T-cell Differentiation Research Articles

O05 Single-cell transcriptomic signature of paradoxical eczema in patients with psoriasis treated with biologics

Abstract Introduction and aims Biologics targeting the tumour necrosis factor (TNF) and the interleukin (IL)-17/23 axis are highly effective treatments for psoriasis but can result in cutaneous adverse events. The pathogenesis of paradoxical eczema, an atopic dermatitis (AD) phenotype occurring after biologic initiation in people with psoriasis, is unknown. This study explored the systemic disease signature of paradoxical eczema. Methods We used single-cell RNA-Seq on peripheral blood mononuclear cells (PBMCs) from three patients with psoriasis with paradoxical eczema, and three matched, biologic-treated controls who had psoriasis. Differential gene expression, gene network expression and cell–cell interaction (using MultiNicheNet) analyses allowed comparison of cases and controls. We assessed overlap between paradoxical eczema and AD using six AD transcriptome datasets. Results Overall, 32 827 PBMCs (14 521 from cases, 18 306 from controls) were included and categorized into 27 clusters. Between cases and controls, there were 727 differentially expressed genes (DEGs) (log fold-change > 0.25, adjusted P < 0.05). A total of 94 of the top 100 DEGs were from monocytes. Significant DEG networks (P < 0.05) mostly mapped to T-cell and monocyte clusters, with commonly enriched pathways in cases including interferon (IFN)-γ, IFN-α, TNF, IL-2/signal transducer and activator of transcription 5 and T-cell differentiation pathways. Cell–cell interaction analysis revealed that the most prioritized interactions in controls, based on differential expression data and known ligand-receptor interactions, included immune regulatory interactions (including ligands such as transforming growth factor β1 and lymphocyte-activation gene 3). In cases, functions of prioritized interactions included chemotaxis, leucocyte activation, T-cell priming and IFN-γ signalling. There was significant enrichment of concordance in the direction of effect of DEGs (65%, P = 5.39 × 10−6) and enriched pathways (85%, P = 3.62 × 10−13) between AD and paradoxical eczema. Conclusions Patients with paradoxical eczema have reduced immune regulatory mechanisms and evidence of monocyte and T-cell activation systemically, with increased production IFN-γ, IFN-α and TNF. There is a significant overlap with the AD transcriptome.

Discovery of Novel Azaindoles as Potent and Selective PI3Kδ Inhibitors for Treatment of Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic autoimmune disorder of the central nervous system and the unmet need for MS treatment demands new therapeutic development. Particularly, PI3Kδ is a high-value target for autoimmune disease, while the investigation of PI3Kδ inhibitors for MS therapy is relatively scarce. Herein, we report a novel class of azaindoles as PI3Kδ inhibitors for MS treatment. Compound 31, designed via nitrogen bioisosterism, displayed excellent PI3Kδ inhibitory activity and selectivity. In vitro assay showed that 31 exhibited superior activity on T lymphocytes to inhibit the proliferation of CD4+, CD8+, and CD3+ T cells. In the experimental autoimmune encephalomyelitis (EAE) model, 31 showed a comparable therapeutical efficacy with Dexamethasone to significantly ameliorate EAE symptoms. Mechanistic studies showed that compound 31 could significantly inhibit the PI3K/AKT/mTOR signaling pathway and inhibited T-cell proliferation and differentiation. Overall, this work provides a new structural PI3Kδ inhibitor and a new vision for MS therapy.

Hotspot DNA Methyltransferase 3A (DNMT3A) and Isocitrate Dehydrogenase 1 and 2 (IDH1/2) Mutations in Acute Myeloid Leukemia and Their Relevance as Targets for Immunotherapy.

DNA methyltransferase 3A (DNMT3A) and isocitrate dehydrogenase 1 and 2 (IDH1/2) are genes involved in epigenetic regulation, each mutated in 7-23% of patients with acute myeloid leukemia. Here, we investigated whether hotspot mutations in these genes encode neoantigens that can be targeted by immunotherapy. Five human B-lymphoblastoid cell lines expressing common HLA class I alleles were transduced with a minigene construct containing mutations that often occur in DNMT3A or IDH1/2. From these minigene-transduced cell lines, peptides were eluted from HLA class I alleles and analyzed using tandem mass spectrometry. The resulting data are available via ProteomeXchange under the identifier PXD050560. Mass spectrometry revealed an HLA-A*01:01-binding DNMT3AR882H peptide and an HLA-B*07:02-binding IDH2R140Q peptide as potential neoantigens. For these neopeptides, peptide-HLA tetramers were produced to search for specific T-cells in healthy individuals. Various T-cell clones were isolated showing specific reactivity against cell lines transduced with full-length DNMT3AR882H or IDH2R140Q genes, while cell lines transduced with wildtype genes were not recognized. One T-cell clone for DNMT3AR882H also reacted against patient-derived acute myeloid leukemia cells with the mutation, while patient samples without the mutation were not recognized, thereby validating the surface presentation of a DNMT3AR882H neoantigen that can potentially be targeted in acute myeloid leukemia via immunotherapy.

Functional characterization of helminth-associated Clostridiales reveals covariates of Treg differentiation

BackgroundParasitic helminths influence the composition of the gut microbiome. However, the microbiomes of individuals living in helminth-endemic regions are understudied. The Orang Asli, an indigenous population in Malaysia with high burdens of the helminth Trichuris trichiura, display microbiotas enriched in Clostridiales, an order of spore-forming obligate anaerobes with immunogenic properties. We previously isolated novel Clostridiales that were enriched in these individuals and found that a subset promoted the Trichuris life cycle. In this study, we aimed to further characterize the functional properties of these bacteria.ResultsClostridiales isolates were profiled for their ability to perform 57 enzymatic reactions and produce short-chain fatty acids (SCFAs) and hydrogen sulfide, revealing that these bacteria were capable of a range of activities associated with metabolism and host response. Consistent with this finding, monocolonization of mice with individual isolates identified bacteria that were potent inducers of regulatory T-cell (Treg) differentiation in the colon. Comparisons between variables revealed by these studies identified enzymatic properties correlated with Treg induction and Trichuris egg hatching.ConclusionWe identified Clostridiales species that are sufficient to induce high levels of Tregs. We also identified a set of metabolic activities linked with Treg differentiation and Trichuris egg hatching mediated by these newly isolated bacteria. Altogether, this study provides functional insights into the microbiotas of individuals residing in a helminth-endemic region.-EyM7p7tfAvrAjtAePB85JVideo

Evaluation of SARS-CoV-2 interferon gamma release assay in BNT162b2 vaccinated healthcare workers.

To predict protective immunity to SARS-CoV-2, cellular immunity seems to be more sensitive than humoral immunity. Through an Interferon-Gamma (IFN-γ) Release Assay (IGRA), we show that, despite a marked decrease in total antibodies, 94.3% of 123 healthcare workers have a positive cellular response 6 months after inoculation with the 2nd dose of BNT162b2 vaccine. Despite the qualitative relationship found, we did not observe a quantitative correlation between IFN-γ and IgG levels against SARS-CoV-2. Using stimulated whole blood from a subset of participants, we confirmed the specific T-cell response to SARS-CoV-2 by dosing elevated levels of the IL-6, IL-10 and TNF-α. Through a 20-month follow-up, we found that none of the infected participants had severe COVID-19 and that the first positive cases were only 12 months after the 2nd dose inoculation. Future studies are needed to understand if IGRA-SARS-CoV-2 can be a powerful diagnostic tool to predict future COVID-19 severe disease, guiding vaccination policies.

Comparative analysis of tabelecleucel and current treatment in patients with Epstein-Barr virus-positive post-transplant lymphoproliferative disease following hematopoietic cell transplant or solid organ transplant

Aims With recent European Union marketing authorization, tabelecleucel is the first off-the-shelf, allogeneic Epstein-Barr virus (EBV)-specific T-cell immunotherapy approved for the treatment of relapsed/refractory EBV-positive post-transplant lymphoproliferative disease (EBV+ PTLD). In the absence of a control arm, real-world evidence can provide a comparative benchmark for single-arm studies in ultra-rare populations. This study assessed the treatment effect of tabelecleucel in the single-arm phase 3 ALLELE study (NCT03394365) versus a treatment group from a multinational, multicenter retrospective chart review study (RS002) of patients with EBV+ PTLD. Methods In ALLELE, patients had disease relapsed/refractory to rituximab ± chemotherapy and received tabelecleucel 2x106 cells/kg on days 1, 8, and 15 in 35-day cycles. Patients in RS002 had disease relapsed/refractory to rituximab ± chemotherapy and received next line of systemic therapy between January 2000 and December 2018. Propensity score-based standardized mortality/morbidity ratio weighting was used to achieve balance between treatment and comparator arms. Kaplan-Meier estimators and Cox regression models were used to compare overall survival (OS) in the re-weighted sample. Results 30 patients (n = 14 hematopoietic cell transplant [HCT], n = 16 solid organ transplant [SOT]) from ALLELE (data cutoff: November 2021) and 84 patients (n = 36 HCT, n = 48 SOT) from RS002 (data lock: January 2021) were included. Median time from diagnosis to first tabelecleucel dose (ALLELE) or start date of next line of systemic therapy (RS002) was 3.6 months. Tabelecleucel was associated with a substantial OS benefit compared with current treatment, with an unadjusted HR of 0.47 (95% confidence interval [CI] 0.25–0.88) and adjusted HR of 0.37 (95% CI 0.20–0.71) when using the start date of the next line of therapy as the index date. Sensitivity analyses yielded consistent results. Conclusions In this study of real-world data, tabelecleucel was associated with an OS benefit among patients with R/R EBV+ PTLD for whom there is high unmet need.

The Possible Roles of IL-4/IL-13 in the Development of Eosinophil-Predominant Severe Asthma.

Bronchial asthma is characterized by airway inflammation, airway hyperresponsiveness, and reversible airway obstruction. Eosinophils contribute to the pathogenesis of airway disease mainly by releasing eosinophil-specific granules, lipid mediators, superoxide anions, and their DNA. Type-2 cytokines such as interleukin (IL)-4 and IL-13 also play roles in the development of bronchial asthma. Among these cytokines, IL-4 is involved in T-cell differentiation, B-cell activation, B-cell differentiation into plasma cells, and the production of immunoglobulin E. Although IL-13 has similar effects to IL-4, IL-13 mainly affects structural cells, such as epithelial cells, smooth muscle cells, and fibroblasts. IL-13 induces the differentiation of goblet cells that produce mucus and induces the airway remodeling, including smooth muscle hypertrophy. IL-4 and IL-13 do not directly activate the effector functions of eosinophils; however, they can induce eosinophilic airway inflammation by upregulating the expression of vascular cell adhesion molecule-1 (for adhesion) and CC chemokine receptor 3 ligands (for migration). Dupilumab, a human anti-IL-4 receptor α monoclonal antibody that inhibits IL-4 and IL-13 signaling, decreases asthma exacerbations and mucus plugs and increases lung function in moderate to severe asthma. In addition, dupilumab is effective for chronic rhinosinusitis with nasal polyps and for atopic dermatitis, and IL-4/IL-13 blocking is expected to suppress allergen sensitization, including transcutaneous sensitization and atopic march.

Abstract PO2-06-12: Patients with metastatic triple-negative breast cancer who receive trilaciclib prior to cytotoxic chemotherapy exhibit improved survival after receiving subsequent anticancer therapy

Abstract Background In an open-label, randomized, phase 2 trial in patients (pts) with metastatic triple-negative breast cancer (mTNBC; NCT02978716), administering trilaciclib prior to gemcitabine plus carboplatin (GCb) significantly prolonged overall survival (OS; a key secondary endpoint) versus administering GCb alone (median 19.8 vs 12.6 months; hazard ratio 0.37; P < 0.0001), with a nonsignificant trend toward improved progression-free survival (median 9.0 vs 5.7 months; hazard ratio 0.62; P = 0.13; Tan et al. Clin Cancer Res. 2022). Given murine data suggesting trilaciclib may preserve the long-term function of hematopoietic stem and progenitor cells (He et al. Sci Transl Med. 2017) and improve T-cell memory (Goel et al. Nature. 2017; Lelliott et al. Cancer Discov. 2021; Heckler et al. Cancer Discov. 2021), we examined survival of pts with mTNBC who received subsequent lines of therapy after receiving GCb with or without trilaciclib. Methods In the phase 2 trial, pts with ≤ 2 prior chemotherapy regimens for locally recurrent or metastatic TNBC were randomized 1:1:1 to receive GCb on days 1 and 8, trilaciclib prior to GCb on days 1 and 8, or trilaciclib alone on days 1 and 8 and prior to GCb on days 2 and 9. The 2 trilaciclib arms were combined for this analysis. To determine if trilaciclib improved outcomes in pts who received additional therapy after GCb, a post hoc survival analysis was performed using data from pts who received any subsequent anticancer therapy (SACT). Results In the subanalysis of data from pts with mTNBC who received any SACT after the phase 2 trial, clinical characteristics such as demographics, disease variables, duration from study treatment to first SACT, and type of SACT were balanced between the trilaciclib (n = 43) and placebo (n = 20) arms. The most common SACTs were gemcitabine, capecitabine, eribulin, taxanes, checkpoint inhibitors, carboplatin, and anthracyclines. Median OS in pts who had previously received trilaciclib was 32.7 months versus 12.8 months in those who had received placebo, with increasing separation of survival curves over time. Median OS from start of first SACT was 17.4 months in the trilaciclib arms vs 5.8 months in the placebo arm. Improved survival and sustained separation of curves was also observed in pts unable to receive SACT (trilaciclib, n = 25; placebo, n = 14), although the magnitude of benefit was smaller (median 9.4 vs 5.4 months). Mechanistic in vivo murine and in vitro human studies are underway to examine the effect of trilaciclib on the generation of memory T cells. These studies will assess the preferential differentiation of specific memory T-cell subsets along with in vivo assessment of memory T-cell responses following a rechallenge. Further data will be presented to evaluate whether the enhanced generation and preservation of a memory T-cell pool is supportive of improved outcomes in pts receiving SACT. Conclusions Data from the phase 2 study suggest that pts with mTNBC who received trilaciclib prior to cytotoxic chemotherapy have prolonged survival, which is notably improved for pts who are able to receive SACT following discontinuation of trilaciclib. The survival benefit from trilaciclib extends to pts who subsequently received immune checkpoint inhibitors and/or chemotherapy, and also to those who did not receive any SACT. Improved OS in pts receiving trilaciclib may be associated with protection of hematopoietic stem and progenitor cells and formation of a memory T-cell pool, which is critical for long-term immune surveillance and in eliciting rapid recall responses. OS will be evaluated in pts with mTNBC in the ongoing phase 3 trial of trilaciclib prior to GCb (PRESERVE 2; NCT04799249) and phase 2 trial of trilaciclib prior to sacituzumab govitecan (NCT05113966). Citation Format: Shom Goel, Joyce O'Shaughnessy, Kun-Hui Lu, Andrew Beelen, Symantha Melemed, John Yi, Michael Danso, Antoinette Tan. Patients with metastatic triple-negative breast cancer who receive trilaciclib prior to cytotoxic chemotherapy exhibit improved survival after receiving subsequent anticancer therapy [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-06-12.

Abstract PO4-16-05: Identification of functional HLA-A*11:01-restricted driver gene PIK3CA mutation specific T-cell receptors

Abstract The adoptive transfer of genetically engineered T-cell receptors (TCR-T) has emerged as a promising therapeutic strategy for the treatment of solid tumors. Recent clinical trials have demonstrated the safety and efficacy of TCR-T cell therapies against certain types of metastatic solid cancers. In our study, we aimed to investigate the potential of TCR-T cell therapies targeting neoantigens, which are exclusively expressed in cancer cells, with a focus on metastatic breast cancer (MBC). Specifically, we identified four driver missense mutations (PIK3CA E542K, E545K, H1047L, and H1047R) frequently observed in MBC patients and utilized computational tools to predict the generation of neoantigens. Utilizing NetMHCpan V.4.1, we performed screening of peptides spanning the mutation region and predicted a neoantigen epitope, PIK3CA_H1047L, to bind with HLA-A*11:01. To validate the presentation and stability of the neoantigen epitope, we employed TAP1-deficient K562 cells and observed stable expression of the mutant peptide-major histocompatibility complex (MHC) complex on the cell membrane. Subsequently, we isolated T cells from healthy donors possessing the HLA-A11:01 genotype, and subjected them to successive stimulations with neopeptide-pulsed dendritic cells. T cells stimulated with neopeptide were examined for neoantigen specificity using an IFN-γ ELISpot assay. Employing pMHC tetramer staining and single-cell sorting via flow cytometry, we successfully isolated five HLA-A11:01-restricted PIK3CA_H1047L-specific TCRs. Through lentivirus transduction of these TCRs into T cells, we achieved the generation of TCR-T cells that exhibited potent and specific activity exclusively against the PIK3CA_H1047L neoantigen. The functionality of the TCR-T cells was confirmed through assessments of CD137 expression, IFN-γ secretion, and cytotoxicity assays. In conclusion, our study demonstrates T cell responses towards neoantigens derived from PIK3CA, a commonly observed driver mutation in MBC. Furthermore, we successfully isolated five distinct neoantigen-specific TCRs that specifically recognized the PIK3CA_H1047L mutation and were restricted to the prevalent HLA-A*11:01 allele. The transfer of these TCRs into T cells resulted in the generation of TCR-T products exhibiting remarkable activity against the PIK3CA_H1047L neoantigen. These findings strongly encourage further investigation into TCRs targeting driver mutations in MBC, with the aim of advancing neoantigen-targeted TCR-T therapies into clinical trials. Additionally, the PIK3CA_H1047L neoantigen holds great promise as a potential candidate for the development of effective cancer vaccines. Citation Format: Meiying Shen, Xiaojian Han, Siyin Chen, Aishun Jin, Shengchun Liu. Identification of functional HLA-A*11:01-restricted driver gene PIK3CA mutation specific T-cell receptors [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-16-05.

Oral administration of Bacillus coagulans TQ-35 alleviates allergic responses in OVA-sensitive BALB/c mice

Bacillus coagulans has been extensively studied so far, but there has been a lack of research on its usage in allergy. In this study, we designed to assess the effect of different concentrations of B. coagulans on food allergy in a BALB/c mouse model of ovalbumin (OVA)-induced food allergy and its effect on gut microbes. The assessment of symptoms, specific immunoglobulin E (IgE), T-cell differentiation, and related gene expression levels in sensitized mice by assay indicated that high doses of oral B. coagulans could alleviate allergic symptoms. Treatment with B. coagulans, in the high-dose group, significantly reduced IgE and IgG1 levels and modulated the balance of T helper type 1 cell (Th1) and Th2 and the expression of relevant genes in the spleen. 16S rRNA analysis showed that probiotics improved the structure of the microbiota, in particular by boosting the percentage of Clostridia, Bacteroides vulgatus and Enterococcus faecium, and by increasing the abundance of microbial species, thereby modulating the immune system. Therefore, this study can provide insights into the practical application of B. coagulans doses to alleviate OVA allergy.

PA28γ induces dendritic cell maturation and activates T-cell immune responses in oral lichen planus.

Oral lichen planus (OLP) is a common chronic inflammatory disease of the oral mucosa, the mechanism of its inflammatory progression has not yet been fully elucidated. PA28γ plays a significant role in a variety of immune-related diseases. However, the exact role of PA28γ in the pathogenesis of OLP remains unclear. Here, we demonstrated that PA28γ is overexpressed in epithelial cells and inflammatory cells of OLP tissues but has no significant relationship with OLP subtypes. Functionally, keratinocytes with high PA28γ expression could induce dendritic cell (DC) maturation and promote the T-cell differentiation into Th1 cells in response to the immune response. In addition, we found that a high level of PA28γ expression is associated with high numbers of infiltrating mature DCs and activated T-cells in OLP tissues. Mechanistically, keratinocytes with high PA28γ expression could promote the secretion of C-C motif chemokine (CCL)5, blocking CCL5 or/and its receptor CD44 could inhibit the induction of T-cell differentiation by keratinocytes with high PA28γ expression. In conclusion, we reveal that keratinocytes with high expression of PA28γ in OLP can induce DC maturation and promote T-cell differentiation through the CCL5-CD44 pathway, providing previously unidentified mechanistic insights into the mechanism of inflammatory progression in OLP.

A CTCF-binding site in the Mdm1-Il22-Ifng locus shapes cytokine expression profiles and plays a critical role in early Th1 cell fate specification

Cytokine expression during Tcell differentiation is a highly regulated process that involves long-range promoter-enhancer and CTCF-CTCF contacts at cytokine loci. Here, we investigated the impact of dynamic chromatin loop formation within the topologically associating domain (TAD) in regulating the expression of interferon gamma (IFN-γ) and interleukin-22 (IL-22); these cytokine loci are closely located in the genome and are associated with complex enhancer landscapes, which are selectively active in type 1 and type 3 lymphocytes. In situ Hi-C analyses revealed inducible TADs that insulated Ifng and Il22 enhancers during Th1 cell differentiation. Targeted deletion of a 17bp boundary motif of these TADs imbalanced Th1- and Th17-associated immunity, both invitro and invivo, upon Toxoplasma gondii infection. In contrast, this boundary element was dispensable for cytokine regulation in natural killer cells. Our findings suggest that precise cytokine regulation relies on lineage- and developmental stage-specific interactions of 3D chromatin architectures and enhancer landscapes.

Rejection resistant CD30.CAR-modified Epstein-Barr virus-specific T cells as an off-the-shelf platform for CD30+ lymphoma

Off-the-shelf (OTS) adoptive T-cell therapies have many benefits such as immediate availability, improved access and reduced cost, but face the major challenges of graft-vs-host disease (GVHD) and graft rejection, mediated by alloreactive T-cells present in the graft and host, respectively. We have developed a platform for OTS T-cell therapies by using Epstein-Bar virus (EBV)-specific T-cells (EBVSTs) expressing a chimeric antigen receptor (CAR) targeting CD30. Allogeneic EBVSTs have not caused GVHD in several clinical trials, while the CD30.CAR, that is effective for the treatment of lymphoma, can also target alloreactive T-cells that upregulate CD30 on activation. Although EBVSTs express high levels of CD30, they were protected from fratricide in cis, by the CD30.CAR. Hence, they could proliferate extensively and maintained function both through their native EBV-specific T-cell receptor (TCR) and the CD30.CAR. The CD30.CAR enabled EBVSTs to persist in co-cultures with naïve and primed alloreactive T-cells and eliminate activated NK cells that can also be alloreactive. In conclusion, we show that CD30.CAR EBVSTs have the potential to be an effective OTS therapy against CD30+ tumors and if successful could then be used as a platform to target other tumor antigens.

Single-cell proteomic analysis of peripheral blood mononuclear cells in patients with pulmonary long COVID

Abstract An estimated 15% of patients are expected to continue to exhibit respiratory symptoms after their SARS-CoV-2 infection. The mechanisms behind these symptoms remain unknown. We recruited twenty-three patients (65% female) who were on average 406 ± 251 days post-COVID-19. The cohort consists of primarily mild (non-hospitalized) patients (87%), with an average age of 43 ± 15 years. Nine of these patients had self-reported dyspnea, which we defined as pulmonary long COVID (PLC). The remaining 14 patients recovered without persistent dyspnea. We performed a 38-panel cytometry by time-of-flight on the peripheral blood mononuclear cells of this cohort. Quality control was performed using FloJo. Further analysis, was done using the CyCombine, CATALYST, and FlowSom packages in R. Our final annotation uncovered 17 different cell clusters. In PLC patients, double-positive T-cells (DPTs) were significantly increased (Wilcoxon p<0.05), indicating that T-cell development or differentiation may be altered in these patients. Though DPTs are known to be increased in females, there was no significant difference in the proportion of DPTs between males and females in our cohort. PLC stem cells had increased expression of CD304 and CD200R (Wilcoxon p<0.05). CD304 is as a co-receptor for SARS-CoV-2, while CD200R is a limiter of pro-inflammatory activity. These findings indicate that the immune landscape in PLC patients is altered, compared to those who recover without residual pulmonary symptoms.

Targeted desialylation and cytolysis of tumour cells by fusing a sialidase to a bispecific T-cell engager.

Bispecific T-cell engagers (BiTEs) bring together tumour cells and cytotoxic T cells by binding to specific cell-surface tumour antigens and T-cell receptors, and have been clinically successful for the treatment of B-cell malignancies. Here we show that a BiTE-sialidase fusion protein enhances the susceptibility of solid tumours to BiTE-mediated cytolysis of tumour cells via targeted desialylation-that is, the removal of terminal sialic acid residues on glycans-at the BiTE-induced T-cell-tumour-cell interface. In xenograft and syngeneic mouse models of leukaemia and of melanoma and breast cancer, and compared with the parental BiTE molecules, targeted desialylation via the BiTE-sialidase fusion proteins enhanced the formation of immunological synapses, T-cell activation and T-cell-mediated tumour-cell cytolysis in the presence of the target antigen. The targeted desialylation of tumour cells may enhance the potency of therapies relying on T-cell engagers.

Joint single-cell transcriptomic and epigenomic analysis reveals key regulators of CAR T cell stemness and antitumor immunity

Abstract The differentiation of antitumor T cells is tightly controlled by transcriptional and epigenetic pathways. Understanding the programs governing the differentiation of therapeutic T cells such as chimeric antigen receptor (CAR) T cells is crucial for improving their efficacy. Using a single-cell multi-omics approach, we simultaneously profiled chromatin accessibility and transcription within the same single CAR T cell in mice with B-cell leukemia or melanoma. One of the CAR T-cell subsets displayed stem cell-like properties and greater proliferative potential upon tumor challenge. In addition, we uncovered primed chromatin states foreshadowing transcriptional changes and lineage-defining genes heavily regulated at the epigenetic level. By constructing gene regulatory networks in CAR T cells based on the single-cell multi-omics data, we identified hub transcription factors of stem-like CAR T cells including BACH2. By knocking out BACH2 in CAR T cells, we demonstrated an essential role of BACH2 in the development of the stem-like subset and antitumor immunity of CAR T cells. Thus, our study elucidated the transcriptional and epigenetic mechanisms underlying CAR T-cell differentiation and revealed key transcriptional regulators controlling the differentiation and antitumor immunity of CAR T cells.

A Role of T-Lymphocyte β-Arrestins in Hypertension

The adaptive immune system and T-cells play a central role in the development of essential hypertension. The renin-angiotensin system regulates blood pressure (BP) through multiple mechanisms including effects on the immune system. Among several G-protein coupled receptors (GPCR) that regulate T-cell function, it has been hypothesized that specific T-cell populations use the angiotensin receptor (AT1R) to modulate immune responses in hypertension. Selective ablation of AT1R in T-cells paradoxically increases hypertensive end-organ damage (EOD). While AT1R typically induces the classical G protein signaling, recent studies have uncovered an alternative protective signaling-cascade at this receptor via β-Arrestin ( ARRB) proteins. Thus, we hypothesized that ARRB in T-lymphocytes mediates an anti-hypertensive and anti-inflammatory role in response to angiotensin II (ANG II) thereby decreasing EOD in hypertension. Transgenic mice with T-lymphocyte-specific knock outs of the Arrb1 gene were developed using a CD4-Cre x Arrb1-Flox system. Hypertensive conditions were modeled with a 3-pronged approach designed to induce kidney damage consisting of unilateral nephrectomy (UNX), maintenance on a 4% salt diet, and a continuous infusion of ANG II (1,000 ng/kg/min). Age and sex-matched Cre negative x Arrb1-Flox littermates were used as controls. BP was measured at baseline before and after UNX, and for the following three weeks using radiotelemetry. Inflammation was assessed using quantitative PCR (q-PCR). Preliminary data suggest that loss of T-cell specific Arrb1 is protective against ANG II-induced hypertension. At baseline CD4Arrb1-null and CD4Arrb1-WT mice had similar systolic BP (123.0±2.9 mmHg and 119.6±2.3 mmHg, respectively, n=5-7). However, CD4Arrb1-null mice exhibited an attenuated response to ANG II infusion after three weeks (162.5±11.8 mmHg vs 187.0±5.9 mmHg n=3-5; p = 0.03). After 15 days of ANG II, mice were placed in metabolic cages and urine was collected. In a 24-hour period, CD4Arrb1-null mice excreted significantly more sodium (1.98±0.07 mg/24hrs vs 1.66±0.03 mg/24hrs, n=3-4; p = 0.01). Tissue collected from the renal cortex following three weeks of ANG II infusion was analyzed for inflammatory cytokines using q-PCR. Gene expression was normalized to 18s expression in CD4Arrb1-WT mice under sham experimental conditions. Expression of tumor necrosis factor α (TNF-α) transcripts was attenuated in CD4Arrb1-null mice when compared to CD4Arrb1-WT (1.62±0.24-fold increase vs 0.67±0.07-fold decrease, respectively, n=3-4; p=0.006). Contrary to our hypothesis, these preliminary data suggest that T-cell Arrb1 does not protect against hypertensive or inflammatory responses to ANG II. However, these studies highlight the role of β-arrestin-1 proteins endogenous to T-lymphocytes in the modulation of the hypertensive response to ANG II. Supported by grants from the AHA and NIH. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Functionalized nanowires for miRNA-mediated therapeutic programming of naïve T cells.

Cellular programming of naïve T cells can improve the efficacy of adoptive T-cell therapy. However, the current ex vivo engineering of T cells requires the pre-activation of T cells, which causes them to lose their naïve state. In this study, cationic-polymer-functionalized nanowires were used to pre-program the fate of primary naïve CD8+ T cells to achieve a therapeutic response in vivo. This was done by delivering single or multiple microRNAs to primary naïve mouse and human CD8+ T cells without pre-activation. The use of nanowires further allowed for the delivery of large, whole lentiviral particles with potential for long-term integration. The combination of deletion and overexpression of miR-29 and miR-130 impacted the ex vivo T-cell differentiation fate from the naïve state. The programming of CD8+ T cells using nanowire-delivered co-delivery of microRNAs resulted in the modulation of T-cell fitness by altering the T-cell proliferation, phenotypic and transcriptional regulation, and secretion of effector molecules. Moreover, the in vivo adoptive transfer of murine CD8+ T cells programmed through the nanowire-mediated dual delivery of microRNAs provided enhanced immune protection against different types of intracellular pathogen (influenza and Listeria monocytogenes). In vivo analyses demonstrated that the simultaneous alteration of miR-29 and miR-130 levels in naïve CD8+ T cells reduces the persistence of canonical memory T cells whereas increases the population of short-lived effector T cells. Nanowires could potentially be used to modulate CD8+ T-cell differentiation and achieve a therapeutic response in vivo without the need for pre-activation.

Comprehensive analysis and prediction model of mitophagy and ferroptosis in primary immune thrombocytopenia.

Primary immune thrombocytopenia (ITP) is linked to specific pathogenic mechanisms, yet its relationship with mitophagy and ferroptosis is poorly understood. This study aimed to identify new biomarkers and explore the role of mitophagy and ferroptosis in ITP pathogenesis. Techniques such as differential analysis, Mfuzz expression pattern clustering, machine learning, gene set enrichment analysis, single-cell RNA sequencing (scRNA-seq) and immune infiltration analysis were employed to investigate the molecular pathways of pivotal genes. Two-sample Mendelian randomization (TSMR) assessed the causal effects in ITP. Key genes identified in the training set included GABARAPL1, S100A8, LIN28A, and GDF9, which demonstrated diagnostic potential in validation sets. Functional analysis indicated these genes' involvement in ubiquitin phosphorylation, PPAR signalling pathway and T-cell differentiation. Immune infiltration analysis revealed increased macrophage presence in ITP, related to the critical genes. scRNA-seq indicated reduced GABARAPL1 expression in ITP bone marrow macrophages. TSMR linked S100A8 with ITP diagnosis, presenting an OR of 0.856 (95% CI = 0.736-0.997, p = 0.045). The study pinpointed four central genes, GABARAPL1, S100A8, LIN28A, and GDF9, tied to mitophagy and ferroptosis in ITP. It posits that diminished GABARAPL1 expression may disrupts ubiquitin phosphorylation and PPAR signalling, impairing mitophagy and inhibiting ferroptosis, leading to immune imbalance.

Interferon-γ Release Assay in the Assessment of Cellular Immunity-A Single-Centre Experience with mRNA SARS-CoV-2 Vaccine in Patients with Juvenile Idiopathic Arthritis.

Background: As the SARS-CoV-2 virus remains one of the main causes of severe respiratory system infections, the Food and Drug Administration strongly advises the continuation of current vaccination programs, including the distribution of updated boosters, especially in high-risk groups of patients. Therefore, there is an unceasing need for further research on the safety and, no less importantly, the clinical effectivity of the vaccines, with an extra focus on cohorts of patients with underlying health problems. This study aimed to assess the efficacy of the SARS-CoV-2 vaccine in possibly immunocompromised children with rheumatic disease while utilizing the interferon-gamma release assay (IGRA) as a marker for COVID-19 immunity in the study follow-up. Methods: This prospective study was performed in a group of 55 pediatric patients diagnosed with juvenile idiopathic arthritis. Eight participants were immunized with the Comirnaty mRNA vaccine before the research commenced, while the rest of the group (n = 47) had not been vaccinated against SARS-CoV-2. At the study baseline, the cellular response to the virus antigen was measured using a specific quantitative IGRA in whole blood; subsequently, the anti-SARS-CoV-2 test was performed, marking the antibodies' levels in serum. Around four months after the enrollment of the last patient in the study, a follow-up survey regarding the events of COVID-19 infection within the cohort was conducted. Results: The study confirmed that all the vaccinated children developed specific T-cell (p = 0.0016) and humoral (p = 0.001 for IgA antibodies, p = 0.008 for IgG antibodies) responses to the inoculation, including those receiving biological treatment and those on conventional disease-modifying anti-rheumatic drugs. The study also showed the different patterns of immunity elicited both after infection and post-vaccination, with higher levels of antibodies and T-cell response after inoculation than after natural exposure to the pathogen. According to the follow-up survey, six children developed PCR-confirmed SARS-CoV-2 infection, whereas the additional 10 patients admitted to having COVID-like symptoms with no laboratory verification. Conclusions: SARS-CoV-2 vaccinations elicit valid immune responses in pediatric rheumatic patients. Including the assessment of T-cell immunity in the evaluation of inoculation-induced immunization can enhance the accuracy of sole humoral response assays.